Although I cannot imagine that authors of normal literature in the framework of teaching and learning will receive lots of money from their publishers, copyright issues in all academic institutions have been a costly discussion for all administrations. We should discuss the alternatives:

You might go to any publishing house`s homepage and look for what is called "legal disclaimer"

A friendly text is included for the whole database in ICDLs Web site: The International Centre for Distance Learning at the Open University.

A form how to cope with the copyright issue in a common way, i.e. to declare the possible legal usage of documents, can be found at the website of Creative Commons Another form is " open content"

The most liberal statement I know of, is by Tony Bates:
This paper is contributed by the author as a means to ensure timely dissemination of scholarly/technical information on a non-commerical basis. Copyright and all rights therein are maintained by the author, despite the fact that this information is offered electronically. It is understood that all individuals copying this information will adhere to the terms/constraints invoked by the author's copyright.

There we have the two positions: I simply favour the latter one!
P.S. Anyone interested in the discussion about this topic, go to Michael Fröhlich, a list of literature on copyright on the Internet! Anyone interested in the worldwide legal discussions go to WIPO or enjoy yourself in a mailing list on this topic!